POSTERO-ANTERIOR RADIOGRAM OF THE KNEE IN WEIGHT-BEARING AND SEMIFLEXION - COMPARISON WITH MR-IMAGING

Purpose: The purpose was four-fold: to assess the reproducibility of p .a. weight bearing radiograms of the knee and the minimal joint-space (MJS) width measure ments in these radiograms; to compare the MJS with MR-detected cartilage defects; to evaluate the location of these cart ilage defects; and to estimate the relation between meniscal abnormali ties and joint-space narrowing. Material and Methods: Fifty-nine indiv iduals, aged 41-58 years (mean 50), with chronic knee pain were examin ed by means of p.a. weight-bearing radiograms in semiflexion with fluo roscopic guidance of the knee joint. The MJS was measured with a stand ard ruler. On the same day MR imaging was performed with proton-densit y-and T2-weighted turbo spin-echo on a 1.0 T imager. Meniscal abnormal ities and cartilage defects in the tibiofemoral joint (TFJ) were noted . Results and Conclusion: The p.a. view of the knee and the MJS measur ements were reproducible. MJS of 3 mm is a limit in diagnosing joint-s pace narrowing in knees with MR-detected cartilage defects. There was a high proportion (p<0.001) of meniscal abnormality within the narrowe d compartments in comparison with those that were not narrowed. A larg er number of the cartilage defects (p<0.05) was found in the medial fe moral condyle than in any of the other condyles of the TFJ. The defect s had a dorsal location (p<0.001) as shown in the weight-bearing radio grams of the knee in semiflexion.